| 摘要 |
The invention relates to a device for taking precise measurements of an aspherical surface by using interference fringes produced by a laser beam. This device consists of a reference gauge 1, onto which the aspherical surface 22 to be measured is pressed. This gauge can move about its centre of curvature C, perpendicularly to its axis of symmetry, and this rotation is interpreted using an angular encoder 7. A laser beam 3, passing through the centre of curvature C of the gauge 1, is reflected on the gauge/surface interface and produces wide interference fringes on a screen 4 fitted with a photodetector 14. The rotation of the gauge allows the beam to scan a half-meridian of the surface. A microcomputer receives the signals from 14 and 7 and calculates the coordinates of the profile. This device is intended for analysing aspherical surfaces, especially of contact lenses. <IMAGE>
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